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Premature Ventricular Contractions (PVCs)

caution
Lead II
25 mm/s10 mm/mV
HR72bpm
RR833ms
QT358ms
Type

Every other beat is a PVC: a fixed alternation of one normal beat and one wide ectopic beat.

Updated

On the trace

Read the strip in this order.

Try each step, then check it.
  1. Find the alternation.
    Show Narrow sinus beat, wide PVC, narrow, wide: every other beat is ectopic.
  2. Check the coupling.
    Show Each PVC sits the same distance after its sinus beat: one focus with a stable trigger.
  3. Check the pause.
    Show Every PVC is followed by a fully compensatory pause, so the sinus beats stay evenly spaced two cycles apart.
  4. Count the rate two ways.
    Show All complexes together give a normal-looking rate, here 72 bpm. The narrow beats alone run at half that, and so may the pulse: an early PVC often ejects too little to be felt.

How to recognise it

FeatureValueNotes
PatternNormal–PVC–Normal–PVCStrictly alternating. A break in the alternation ends the bigeminy until it restarts.
Coupling intervalFixedThe same sinus-to-PVC interval throughout.
PVC burden50%On this strip. The true daily burden needs a Holter.
RateAppears normalAll complexes counted it matches the sinus rate; the palpable pulse can be half of it.

The strip

Thirty seconds of ventricular bigeminy in lead II, drawn by the simulator. Work through the steps above on it: find the alternation, then check the coupling and the pause.
Go deeper

Background

Bigeminy matters mechanically: half the beats are dyssynchronous and eject poorly, so the pulse can be half the monitor rate, and bigeminy sustained through the day carries a real risk of PVC-induced cardiomyopathy.

Management

1

Measure the real burden

A strip shows 50%, but only a Holter shows how long the bigeminy lasts. Sustained for much of the day, it is well into the range where PVC-induced LV dysfunction occurs, and echocardiography is indicated.

2

Look for the cause

Bigeminy is classically linked to digoxin toxicity and low potassium. Check the drug list and electrolytes before any antiarrhythmic.

Differential

Premature Ventricular Contractions (PVCs)

The same beats without the fixed pattern: wide beats scattered at irregular intervals are isolated ectopy.

Ventricular Trigeminy

Two sinus beats before each PVC instead of one: a three-beat cycle and a burden of about 33%.

The full picturePremature Ventricular Contractions (PVCs)Mechanism, causes and management are covered in the base rhythm.

References

  1. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death — European Heart Journal, 2022